mojo/system/local_data_pipe.h

   1 // Copyright 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef MOJO_SYSTEM_LOCAL_DATA_PIPE_H_
   6 #define MOJO_SYSTEM_LOCAL_DATA_PIPE_H_
   7
   8 #include "base/basictypes.h"
   9 #include "base/memory/aligned_memory.h"
  10 #include "base/memory/ref_counted.h"
  11 #include "base/memory/scoped_ptr.h"
  12 #include "mojo/system/data_pipe.h"
  13 #include "mojo/system/system_impl_export.h"
  14
  15 namespace mojo {
  16 namespace system {
  17
  18 // |LocalDataPipe| is a subclass that "implements" |DataPipe| for data pipes
  19 // whose producer and consumer are both local. This class is thread-safe (with
  20 // protection provided by |DataPipe|'s |lock_|.
  21 class MOJO_SYSTEM_IMPL_EXPORT LocalDataPipe : public DataPipe {
  22  public:
  23   // |validated_options| should be the output of |DataPipe::ValidateOptions()|.
  24   // In particular: |struct_size| is ignored (so |validated_options| must be the
  25   // current version of the struct) and |capacity_num_bytes| must be nonzero.
  26   explicit LocalDataPipe(const MojoCreateDataPipeOptions& validated_options);
  27
  28  private:
  29   friend class base::RefCountedThreadSafe<LocalDataPipe>;
  30   virtual ~LocalDataPipe();
  31
  32   // |DataPipe| implementation:
  33   virtual void ProducerCloseImplNoLock() OVERRIDE;
  34   virtual MojoResult ProducerWriteDataImplNoLock(const void* elements,
  35                                                  uint32_t* num_bytes,
  36                                                  bool all_or_none) OVERRIDE;
  37   virtual MojoResult ProducerBeginWriteDataImplNoLock(
  38       void** buffer,
  39       uint32_t* buffer_num_bytes,
  40       bool all_or_none) OVERRIDE;
  41   virtual MojoResult ProducerEndWriteDataImplNoLock(
  42       uint32_t num_bytes_written) OVERRIDE;
  43   virtual MojoWaitFlags ProducerSatisfiedFlagsNoLock() OVERRIDE;
  44   virtual MojoWaitFlags ProducerSatisfiableFlagsNoLock() OVERRIDE;
  45   virtual void ConsumerCloseImplNoLock() OVERRIDE;
  46   virtual MojoResult ConsumerReadDataImplNoLock(void* elements,
  47                                                 uint32_t* num_bytes,
  48                                                 bool all_or_none) OVERRIDE;
  49   virtual MojoResult ConsumerDiscardDataImplNoLock(uint32_t* num_bytes,
  50                                                    bool all_or_none) OVERRIDE;
  51   virtual MojoResult ConsumerQueryDataImplNoLock(uint32_t* num_bytes) OVERRIDE;
  52   virtual MojoResult ConsumerBeginReadDataImplNoLock(const void** buffer,
  53                                                      uint32_t* buffer_num_bytes,
  54                                                      bool all_or_none) OVERRIDE;
  55   virtual MojoResult ConsumerEndReadDataImplNoLock(
  56       uint32_t num_bytes_read) OVERRIDE;
  57   virtual MojoWaitFlags ConsumerSatisfiedFlagsNoLock() OVERRIDE;
  58   virtual MojoWaitFlags ConsumerSatisfiableFlagsNoLock() OVERRIDE;
  59
  60   void EnsureBufferNoLock();
  61   void DestroyBufferNoLock();
  62
  63   // Get the maximum (single) write/read size right now (in number of elements);
  64   // result fits in a |uint32_t|.
  65   size_t GetMaxNumBytesToWriteNoLock();
  66   size_t GetMaxNumBytesToReadNoLock();
  67
  68   // Marks the given number of bytes as consumed/discarded. |num_bytes| must be
  69   // greater than |current_num_bytes_|.
  70   void MarkDataAsConsumedNoLock(size_t num_bytes);
  71
  72   // The members below are protected by |DataPipe|'s |lock_|:
  73   scoped_ptr<char, base::AlignedFreeDeleter> buffer_;
  74   // Circular buffer.
  75   size_t start_index_;
  76   size_t current_num_bytes_;
  77
  78   DISALLOW_COPY_AND_ASSIGN(LocalDataPipe);
  79 };
  80
  81 }  // namespace system
  82 }  // namespace mojo
  83
  84 #endif  // MOJO_SYSTEM_LOCAL_DATA_PIPE_H_